What medications are used for trigger point injections?

Medications for Trigger Point Injections

Local anesthetics (lidocaine or bupivacaine) are the primary medications used for trigger point injections, with the addition of corticosteroids providing minimal additional benefit and not recommended for routine use. 1, 2, 3, 4

Primary Injectate Options

Local Anesthetics (First-Line)

• Lidocaine 0.5% is the most commonly recommended local anesthetic for trigger point injections, with evidence showing 52% improvement versus 30% with saline placebo at 2 weeks (p=0.05) 3
• Bupivacaine can be used as an alternative local anesthetic, particularly when longer duration of action is desired 5, 6
• Typical injection volume is 2 mL per trigger point 6
• Dry needling alone (without any medication) may be equally effective as medication injection (63% vs 42% pain reduction, p=0.09), suggesting the mechanical needle stimulation itself provides therapeutic benefit 3, 4

Corticosteroid Addition (Not Routinely Recommended)

• The addition of corticosteroids to local anesthetics provides minimal benefit for trigger point injections and is not recommended for routine use 1, 2, 4
• When corticosteroids are used, non-particulate corticosteroids are preferred to minimize adverse events 4
• If a corticosteroid is added, options include:
  • Dexamethasone 4 mg/mL mixed 1:1 with local anesthetic 6
  • Methylprednisolone (though associated with higher rates of eventual surgical intervention in trigger finger studies) 7
  • Triamcinolone (associated with higher rates of requiring additional injections) 7
• The addition of steroids to lidocaine does not improve outcomes beyond lidocaine alone for trigger point therapy 3

Specific Formulations by Clinical Context

For Myofascial Pain (Trapezius, Lumbar Back)

• Lidocaine 0.5% alone is recommended 2, 3
• Volume: typically 0.5-2 mL per trigger point 3
• Corticosteroid addition provides no demonstrated long-term benefit 1, 2

For Post-Mastectomy Pain Syndrome

• 1:1 mixture of 0.5% bupivacaine and 4 mg/mL dexamethasone (2 mL total volume) showed 91.2% success rate with mean follow-up of 43.9 months 6
• 72.3% of successful cases required only a single injection 6

For Trigger Finger (Tendon Sheath Injection)

• Corticosteroid combined with lidocaine is more effective than lidocaine alone for trigger finger specifically (relative risk = 3.15; 95% CI, 1.34-7.40; NNT = 3) 8
• This represents an exception where corticosteroid addition is beneficial 8
• Choice of corticosteroid matters: triamcinolone requires more repeat injections, while methylprednisolone leads to earlier surgical intervention 7

Critical Safety Considerations

Dosing Restrictions

• Maximum of 4 injection sessions over no more than 8 months 1, 2, 3
• Injections should not be repeated more frequently than once every 2 months if therapeutic effect is achieved 2, 3
• Additional injections are not medically necessary if no clinical response was achieved from previous injections 2, 3

Monitoring Requirements

• Document baseline pain scores, functional status, and duration of relief after each injection 2, 3
• Injections should only be repeated if there was documented quantifiable improvement from the previous injection 2, 3
• Expected pain relief duration: approximately 2 weeks to 2 months per injection 3

Adverse Events

• Rare but serious complications include infection, spinal epidural abscess, and meningitis 3
• Severe hypokalemic paralysis has been reported with methylprednisolone-containing injections (serum potassium 1.7 mmol/L within 12 hours) 9
• Corticosteroid-related adverse events include increased blood glucose, decreased bone mineral density, and hypothalamic-pituitary axis suppression 4
• Lidocaine may cause methemoglobinemia, CNS toxicity (restlessness, anxiety, tinnitus, dizziness, tremors), and cardiovascular effects 5, 10

Common Clinical Pitfalls to Avoid

• Performing repeated injections without documented improvement represents inappropriate care and lacks medical necessity 2, 3
• Using trigger point injections as long-term pain management is not recommended as these are temporary symptomatic treatments only 1, 2, 3
• Failing to implement concurrent physical therapy is a common error, as injections should facilitate participation in active rehabilitation, not replace it 3
• Adding corticosteroids routinely to trigger point injections when evidence shows minimal benefit beyond local anesthetic alone 1, 2, 4